1. Field
One or more embodiments of the present invention relate to an organic light emitting display apparatus and a method of fabricating the same, and more particularly, to an organic light emitting display apparatus having an improved stack structure so as to reduce the number of mask used and a method of fabricating the organic light emitting display apparatus.
2. Description of the Related Art
Recently, flat panel display apparatuses, which may be portable, are widely used as display apparatuses. Among flat panel display apparatuses, electroluminescence display apparatuses are self-emission type display apparatuses, which have a wide viewing angle, excellent contrast, and a fast response speed, and thus, are considered as next generation display apparatuses. In addition, organic light emitting display apparatuses, in which a light emitting layer is formed of an organic material, have higher brightness, superior driving voltages, and faster response speeds than those of inorganic light emitting display apparatuses, and may realize multiple colors.
Organic light emitting display apparatuses include a thin film transistor (TFT) unit and an organic light emitting device driven by the TFT unit to emit light. The TFT unit may be formed by stacking a conductor, a semiconductor, and an insulating layer on a substrate, and forming a TFT including a driving transistor and a switching transistor, a capacitor, data lines, scan lines, and pixel units for controlling the organic light emitting device. The TFT unit may be fabricated by a photoresist process by using a mask.
However, since the data lines and the scan lines cross each other on the substrate, it is difficult to dispose the data lines and the scan lines in the same layer. Therefore, the data lines and the scan lines are disposed in different layers, separated by the insulating layer, according to the conventional art. However, when the number of stacked layers increases, processes of exposing patterns by using a mask and etching are additionally performed. Therefore, fabrication processes become complex as the number of stacks increases.
Recently, a half-tone mask has been used to reduce the number of masks used; however, exposure degrees vary depending on portions exposed when using a mask once. Therefore, it is very difficult to perform the process described above, and thus, defective rate of products is increased.
In addition, since the substrate has increased in sized in order to realize a large screen, low resistance wires are necessary, and thus, the data lines and scan lines are formed to be thick. However, the insulating layer disposed between the data lines and the scan lines, which are disposed in different layers, should be thicker than the data lines and the scan lines in order to prevent an electric short from generating where the data lines and the scan lines intersect.